Page 2 of 2 FirstFirst 12
Results 16 to 25 of 25
  1. #16
    Join Date
    May 2009
    Location
    NSW
    Posts
    489

    Default

    I think I will investigate the ins and outs of making some sort of viewing window in the domed lid, or perhaps look for a tall and skinny container of suitably stout construction. I will assume that the smaller the opening then the thinner the PC sheet can be? If that is so then the cylinder can be tall and skinny and hold material stacked on end rather than side-by-side? Who knows what silly ideas I might come up with?

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Posts
    Many





     
  3. #17
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,757

    Default

    Quote Originally Posted by Old Hilly View Post
    I think I will investigate the ins and outs of making some sort of viewing window in the domed lid, or perhaps look for a tall and skinny container of suitably stout construction. I will assume that the smaller the opening then the thinner the PC sheet can be? If that is so then the cylinder can be tall and skinny and hold material stacked on end rather than side-by-side? Who knows what silly ideas I might come up with?
    For a simple long skinny vacuum pot a length of PVC sewage pipe can be used on its side, with push fit cap glued on at one end and a screw capped coupler as a lid.
    Stuff can be slid into the tube on long trays
    If you have several days of free time there are heaps of these on youtube, including loads and loads of fails.
    I personally wouldn't use PVC for long term use as it is likely to eventually fail no matter what you do.

  4. #18
    Join Date
    Aug 2007
    Location
    Saskatoon, SK, Canada.
    Posts
    1,436

    Default

    If you are not drilling the top have you considered tempered glass? It's possible a glass shop might have a thicker piece. These are bigger than you need but the price is right.

    Round Table Top Tempered Glass Chopping Board Multiple Size 10-12mm thick | eBay

    Pete

  5. #19
    Join Date
    May 2009
    Location
    NSW
    Posts
    489

    Default

    I had thought of using glass and some vacuum chamber manufacturers do use it but I worry about what will happen if the stuff fails when under vacuum. Will it just crack or will there be a massive implosion with bits of glass flying all over the place? I sort-of like the idea of a gradual and dignified failure rather than a newsworthy major disaster.

  6. #20
    Join Date
    Aug 2007
    Location
    Saskatoon, SK, Canada.
    Posts
    1,436

    Default

    You trust tempered glass a foot from your ear every time you get in your car and it is half or less as thick. Glass shops can get it thicker but there is a cost.

    Pete

  7. #21
    Join Date
    May 2009
    Location
    NSW
    Posts
    489

    Default

    And it shatters really easily, that's why I don't trust it for a vacuum chamber. I have a friend who is a locksmith and his experience fitting locks to glass doors reinforces my fear of the stuff.

  8. #22
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    27,757

    Default

    At work we used many gas plates as vacuum chamber covers. It doesn't make much difference, but the vacuum was about 0.000000001 atm
    The old ones were pain 3/4" thick plate glass covering a 120mm opening. If these broke under vacuum it was not a good thing. I was not there but one did break - no one was injured but glass was scattered all over the lab.

    Because of this we switched to plates made of two 6mm plates of safety glass sandwiching a 1mm layer of silicone. We broken a number of these, once it was under vacuum but it was a non-event. The glass cracked and the silicone prevented it from imploding just long enough so the vacuum is released. Other plates were dropped and once a student dropped a spanner on one cracking it. We used to buy this glass from a regular glass supplier. You can make your own silicone sandwich plate from oven door glass plates. Better still would be sandwiches from tempered glass and PC, glass on the inside of the chamber so fumes won't worry it and PC on the outside for safety.

    An alternative is to use a mesh guard to cover the glass plate. We had several 15L glass bell jars that were used under vacuum covered with steel mesh made of 1mm thick steel perforated with 1/4" holes with a 1/4" spacing. It was surprisingly easy to see through. This prevents the glass getting a hard knock while under vacuum which is when they are most likely to break.

    I've worked with PC and glass in and around labs and workshops for many years and this is why I like PC.
    As I get my PC for free, if the fume eventually fog it My intention is to just replace it.

  9. #23
    Join Date
    May 2009
    Location
    NSW
    Posts
    489

    Default

    So what sort of silicone did you use between the glass plates? I need to be able to see through the glass to be able to observe the off-gassing of the timber so the "juice" doesn't boil over and mess up the internals of the pot or get sucked into the vacuum pump. Was this ordinary silicone suitable for glass or something more specialised?

  10. #24
    Join Date
    Feb 2018
    Location
    Ipswich
    Posts
    103

    Default

    An A3 sheet of 12mm PC is $24 here
    300 x 300 $17

  11. #25
    Join Date
    May 2009
    Location
    NSW
    Posts
    489

    Default

    That was so cheap I ordered 2 @300x300! But I have plans for another chamber so I might as well save on postage. Thanks for the research!

Page 2 of 2 FirstFirst 12

Similar Threads

  1. Replies: 3
    Last Post: 25th May 2021, 12:13 PM
  2. Replies: 1
    Last Post: 2nd November 2017, 10:02 PM
  3. What I did last week - quick build quick canoe?
    By Boatmik in forum Michael Storer Wooden Boat Plans
    Replies: 4
    Last Post: 9th August 2010, 11:14 AM
  4. Quick ! Quick, ya Stanley collecting freaks..a stanley # 1 !
    By JDarvall in forum HAND TOOLS - POWERED
    Replies: 29
    Last Post: 17th March 2006, 09:17 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •